1. Chromatin fibres condense and supercoil to form chromosomes. The chromosomes become visible under a light microscope.2. Cylindrical bundles of proteins called the centrioles move to either end of the cell.3. The nucleolus disappears and the nuclear membrane disintegrates.4. Microtubules form the nuclear spindle from the centrioles, stretching from the poles to the equator.5. The spindle fibres attach to the centromeres and start moving the chromosomes to the middle of the cell.6. By the end of prophase the nuclear membrane has disappeared.